MINNETONKA, Minnesota (October 1, 2014) – OneBeacon Entertainment (OBE), a member of OneBeacon Insurance Group (NYSE: OB), today announced that it has opened an office in Chicago, Ill. led by Mark Stuckel. In this new role, Stuckel reports to Brenda Campbell, from the Los Angeles office.

OBE President Peter Williams said, “We are very pleased to welcome Mark to OneBeacon and especially excited to establish a presence in Chicago. Mark’s longtime focus on the casino and gaming industry brings the expertise required to serve our Midwest clients and build on our strong foundation in this entertainment sector.”

Stuckel comes to OneBeacon with 35 years of underwriting experience, much of which was spent serving in various underwriting and management roles at Zurich North America. Over that time, he has specifically focused on the entertainment insurance segment, with a particular expertise in the casino and gaming sector.

About OneBeacon: OneBeacon Insurance Group, Ltd. is a Bermuda-domiciled holding company that is publicly traded on the New York Stock Exchange under the symbol "OB." OneBeacon's underwriting companies offer a range of specialty insurance products sold through independent agencies, regional and national brokers, wholesalers and managing general agencies. Each business is managed by an experienced team of specialty insurance professionals focused on a specific customer group or industry segment, and providing distinct products and tailored coverages and services. OneBeacon's solutions target ocean and inland marine; entertainment, sports and leisure; group accident; crop; public entities; technology; tuition refund; professional liability; environmental; excess property; programs; and commercial surety. For further information about our products and services visit: www.onebeacon.com and to remain up to date on OneBeacon's news, follow us on Twitter @OneBeaconIns or visit our online newsroom: www.onebeacon.com/newsroom.

This press release may contain "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. All statements, other than statements of historical facts, included or referenced in this press release that address activities, events or developments which we expect will or may occur in the future are forward-looking statements. The words "will," "believe," "intend," "expect," "anticipate," "project," "estimate," "predict," "anticipate" and similar expressions are also intended to identify forward-looking statements. These forward-looking statements include, among others, statements with respect to OneBeacon's:

These statements are based on certain assumptions and analyses made by us in light of OneBeacon's experience and judgments about historical trends, current conditions and expected future developments, as well as other factors believed to be appropriate in the circumstances. However, whether actual results and developments will conform to our expectations is subject to a number of risks, uncertainties or other factors which are described in more detail, that could cause actual results to differ materially from expectations, including:

• competitive forces and the cyclicality of the property and casualty insurance industry;

• actions taken by rating agencies from time to time with respect to us, such as financial strength or credit rating downgrades or placing our ratings on negative watch;

• the continued availability of capital and financing;

• the outcome of litigation and other legal or regulatory proceedings;

• our ability to retain key personnel;

• our ability to continue meeting our debt and related service obligations or to pay dividends;

• the continued availability and cost of reinsurance coverage and our ability to collect reinsurance recoverables;

• the ability of our technology resources to prevent a data breach and the ability of our internal controls to ensure compliance with legal and regulatory policies;

• our ability to successfully develop new specialty businesses;

• changes in laws or regulations, or their interpretations, which are applicable to us, our competitors, our agents or our customers;

• participation in guaranty funds and mandatory market mechanisms;

• the impact of new theories of liability;

• changes to current shareholder dividend practice and regulatory restrictions on dividends;

• our status as a subsidiary of White Mountains, including potential conflicts of interest;

• whether the sale of our runoff business closes; and

• other factors, most of which are beyond our control, including the risks that are described from time to time in OneBeacon's filings with the Securities and Exchange Commission, including but not limited to OneBeacon's Annual Report on Form 10-K for the fiscal year ended December 31, 2013 filed February 28, 2014.

Consequently, all of the forward-looking statements made in this press release are qualified by these cautionary statements, and there can be no assurance that the anticipated results or developments will be realized or, even if substantially realized, that they will have the expected consequences. OneBeacon assumes no obligation to update publicly any such forward-looking statements, whether as a result of new information, future events or otherwise.